Born in Colombia to an American father and Colombian mother, Taddeo-Goldstein, 47, is vice-chairwoman of the Florida Democratic Party and a member of the Democratic National Committee.

"She's a working mom, she's a great Floridian, she has a heart of gold," Crist told a Miami press conference on Thursday.

Taddeo-Goldstein is expected to boost Crist's support in South Florida's large Hispanic community, as well as among women voters, if he wins the Democratic primary for November's race against Rick Scott, the incumbent Republican governor.

If elected, she would be the first Hispanic female lieutenant governor of Florida. Scott also has a Hispanic running mate, the current lieutenant governor, Carlos López-Cantera, 40, who was born in Spain to parents of Cuban origin.

Crist is former Republican who served as governor from 2007-2011 before running for the U.S. Senate as an independent in 2010, losing to Senator Marco Rubio. He officially registered as a Democrat in late 2012.

His Democratic party opponent, former state Senator Nan Rich, said it was “arrogant” for Crist to make his choice now, before an Aug. 26 primary.

"The voters are going to focus on who’s running for governor, and he needs to focus on that as well,” she said.

Crist’s choice will help him establish credibility with lifelong Democrats, said Democratic National Committee member Jon Ausman of Tallahassee.

“He needed somebody from one of the big three counties – Miami-Dade, Broward and Palm Beach, which have one-third of the primary vote,” said Ausman, a Crist supporter.

In addition to being one of five vice-chairs of the state party, Taddeo-Goldstein is close to DNC chairwoman Debbie Wasserman Schultz, a Broward congresswoman, Ausman noted.

Taddeo-Goldstein moved to the United States at age 17 and is chief executive of a Miami-area language services company.

"As a working mom, as a small business owner and a proud Floridian I am thrilled at the opportunity to serve as lieutenant governor of the state," she told reporters.

"I know what it's like to live on the minimum wage; I know what it's like as a small business owner to worry whether or not you'll be able to make payroll," she added.

Taddeo-Goldstein was born on a U.S. military base in Colombia, where her father met her mother while he was serving in the armed forces, according to her website. She holds a degree in commercial Spanish and business administration, and is married to Eric Goldstein, a clinical psychologist and motivational speaker.

(Additional reporting by Bill Cotterell in Tallahassee; Writing by David Adams; Editing by Jim Loney)